How to find portal installation directory

Hi

I am having a portal implementation up and running.

Now I need to modify a par file in that portal.

I know the name of this par file and I am able to find it in "System Administration."

The problem is that all PAR uploaded there are of size 0.

Now, I remember that if you deploy a par file in portal, it gets deplyed in your J2EE server.

In my case I dont' know what is the name of this server directory.

And thus not able to browse by deployables in server file system using:

<J2EE-Install-Dir>\Path to portal deployed applications.

How can I find this <J2EE-Install-Dir>.